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Sudden weather change leads to first biological extinction |
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16:22, July 05, 2007 |
The Nanjing Institute of Geology and Paleontology, of the Chinese Academy of Sciences, announced that after ten years of studies, China's paleontologists confirmed that a sudden change in climate led to the extinction of the Ordovician period.
Five major biological extinctions have occurred on earth. The first extinction occurred in the late Ordovician period, about 440 million years ago. The reason for the first biological extinction has always been a hot point of paleontological research. Some believe that it was because a meteorite hit the earth, some think that a warm climate suddenly turned into an ice age, and some experts even believe that the release of gamma rays led to the extinction.
After ten years of study, experts finally attributed a sudden change of climate to this period's extinction. Fan Juanxuan, a doctor at the Nanjing Institute of Geology and Paleontology, of the Chinese Academy of Sciences, said that his research team had collected specimens in more than 100 geological sites of southern China. After ten years of fossil analysis, they narrowed down the biological variety change within a 100,000 year scale for the first time.
The research confirmed that the extinction occurred in two waves. The first biological extinction occurred 446 million years ago because the climate suddenly turned cold, and the Antarctic icecap rapidly expanded. The sea level decreased by more than 150 meters. This also led to the sudden decrease in the living space of marine life. Marine animals, including the graptolite and trilobite, slowed down their metabolisms thereafter. A portion of living things that survived the disaster experienced a second extinction thereafter -- a sudden warm climate and a rapidly rising sea level all led to biological extinction again. Due to complete evidence, this theory has been generally recognized by domestic and foreign experts.
By people's Daily Online
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